1036
NOTES
obtained. The mother liquor was concentrated and the products separated by chromatography. The yield of N*benzyl-N~-butyl-N2-methyl-N1-phenyl-1,2 propanediamine, n y 1.5497, was 420 mg. The infrared absorption spectrum had a more intense alkyl band than the analogous Nl-ethyl compound and lacked a CO or N H band. A&. Calcd. for CZ1H3~N2: C, 81.2; H, 9.7; N, 9.0. Found: C, 80.3: H. 9.8: N. 9.0. 'The dipicrate was prepared and recrystallized from ethanol, m.p. 99-100". Anal. Calcd. for C33H36N8014: C, 51.4; H, 4.7; N, 14.6. Found: C, 51.5; H, 5.2; N, 14.4. N-( &Benzylmethylaminopropyl)acetanilide (V). This compound was prepared by the reaction of Nkbenzyl-NLmethylN1-phenyl-1,Zpropanediamine with acetic anhydride. The yield of N-(2-benzylmethylaminopropyl)acetanilide, b.p. 150-156°/0.1 mm. andn'," 1.5552, was 86%. Anal. Calcd. for Cl9HzrNz0: C, 77.0; H, 8.2; h',9.4. Found: C, 76.7; H, 8.2; N, 9.3. N-(bBenzylmethylaminopropy1)butyranilide (VII). This compound, b.p. 165-167"/0.2 mm. and n'," 1.5446, was obtained in 80yoyield by the reaction of N2-benzyl-N2-methylNLphenyl-1,2-propanediamine with butyric anhydride. Anal. Calcd. for Cz1HzsN20:C, 77.7; H, 8.7; N, 8.6. Found: C, 77.6; H, 9.0; N, 8.6.
VOL.
25
-
Acknowledgment. We are indebted to Dr. J. H. Clark and associates and to Mr. H. J. Brabander for the preparation of some of the intermediates, to Mr. C. Pidacks and co-workers for the chromatography, and to Mr. L. Brancone and Mr. W. Fulmor and associates for the microanalyses and infrared absorption spectra. ORGANIC CHEMICAL RESEARCH SECTION LEDERLELABORATORIES DIVISION AMERICAN CYANAMID COMPANY PEARL RIVER,N. Y.
I
f
I11
2
11
0::; CHs
G h H 2
OPN\
NO? IV
v
NO,
dinitro-o-iodotoluene (111) from 4,6-dinitro-o-toluidine5failed. 3,4-Dinitro-o-iodotoluene (I) has also been synthesized from 3,4-dinitro-o-toluidine* (IV). 4,5-Dinitro-o-iodotoluene (11) behaves normally with hydrazine hydrate giving 2-nitrod-iodo-ptolylhydrazine as the main product. The structure is assigned by analogy with other hydrazine preparations.2 The various dinitroiodo isomers prepared above can be distinguished readily, by taking advantage of their color reactions in acetone solution with aqueous sodium hydroxide, in which colors ranging from light red to intense green are produced.
EXPERIMENTAL^
Nitration of 4-nitro-o-iodotohene. To a suspension of 4nitro-o-iodotoluene (10 g.) in concd. sulfuric acid (42 ml., d. 1.8), fuming nitric acid (14 ml., d. 1.5) was added dropwise with vigorous shaking. It was then heated on a Water bath for about 2 hr. and poured on crushed ice. The yellow The Nitration of 4-Nitro-o-iodotoluene crystalline material which separated was repeatedly crystall i e d successively from ethanol and methanol to give 4,5R. S. KAPIL~ dinitro-o-iodotoluene (5.2 9.) as yellow flakes, m.p. 97". Anal. Calcd. for C7H604N21:I, 41.2. Found: I, 41.0. The mother-liquor on standing deposited crystals of 4,6Received November 8, 1969 dinitro-o-iodotoluene ( 1 g.) which crystallized from ethanol as pale yellow needles, m.p. 178'. Dinitroiodo compounds have received little atAnal. Calcd. for C7H604NNzI: I, 41.2. Found: I, 40.8. tention, as only a few of them are described in the There remained an oil (1.5 g.) which could not be induced literature. During a program of research on ni- to crystallize. 3,4- and 4,6-Dinitro-o-loluddines4were prepared according tration of some iodo2J compounds in this laborato the method described previously. tory, nitration of 4-nitro-o-iodotoluene was under4,5-Dinitro-o-io~toluene.4,5-Dinitro-o-toluidine (0.5 g.) taken for detailed investigation. The reaction can dissolved in concd. sulfuric acid (5 g.) containing a little be expected to give three dinitro isomers, viz., 3,4- water was diazotized at 0' with sodium nitrite (0.4 g.), (I) ; 4, 5-(11) and 4,6-(111) dinitro-o-iodotoluenes. After 0.5 hr. the mixture was treated with a solution of Only two isomers, Le., 4,5-dinitro-(II) and 4,6- potassium iodide (5 g.) in water. The 4,5-dinitro-o-iodotoluene formed was isolated in the usual manner and dinitro-o-iodotoluene (111) , were isolated from the recrystallized from ethanol as yellow flakes (0.4 g.), m.p. reaction mixture. The identity of 4,5-dinitro-o- 96'; mixed melting point with a sample of 4,5-dinitro-oiodotoluene (11) was confirmed by an unequivocal iodotoluene obtained by nitration of 4nitro-o-iodotoluene synthesis from 4,5-dinitro-o-toluidine4 (V) by remained undepressed. S,4-Dinitro-o~odotoluenewas prepared by adopting a Sandmeyer's reaction. Attempts to prepare 4,6- procedure, similar to that described above, from 3,4dinitro-o-toluidine as pale yellow needles, m.p. 117'. Anal. Calcd. for C7HsOJVNeI: I, 41.2. Found: I, 40.7. (1) Present address: Central Drug Research Institute, &Nitro-6-wdo-pto~ythydrazine. To a solution of 4,5Lucknow (India). dinitro-o-iodotoluene ( 5 g.) in ethanol twice the equivalent ( 2 ) R. S. Kapjl, J. Chem. Soc., 24,4127 (1959). (3) R. S. Kapil, J. Org. Chem., in press. (4) 0. L. Brady and P. N. Williams, J . Chem. SOC.,117, ( 5 ) R. S. Kapil, J . Indian Chem. SOC.,in press. 1137 (1920). (6) All melting points are uncorrected.
JUNE
1960
NOTES
1037
The nitration of tribromobenzene was carried out in two steps. Because the singular position of the bromine atoms ortho, ortho, para to the three open positions on the ring should enhance ring reactivity only mild conditions were used for the dinitration of 1,3,5-tribromobenzene in contrast to prolonged reaction periods a t reflux temperature in earlier work.3 This compound was easily nitrated in nearly quantitative yield a t 25-60' by mixed fuming nitric acid and commercial concentrated sulfuric acid in less than'an hour. However if the nitration mixture were held a t this temperature after nitration was complete bromine evolution occurred. The nitration of the sixth position required o-Iodotoluenes Colors Produced more drastic conditions because of the intense Intense green 3,4-Dinitrodeactivation effect of the nitro groups and steric Light red 4,B-Dinitrohindrance of the bromine atoms ortho to the open Violet 4,g-Dinitroposition. Because of the low yields and extensive decomposition encountered by previous workers Acknowledgment. The author's thanks are due to in nitrating with mixed acids this method of niDr. S. S. Joshi, D.Sc., Principal, Meerut College, tration was not further investigated. Instead niMeerut (India) for his kind interest in this work. tration of 1,3,5-tribromo-2,4-dinitrobenzeneby a solution of potassium nitrate dissolved in fuming DEPARTMENT OF CHEMISTRY sulfuric acid gave yields up to 74% without excesMEERUTCOLLEGE MEERUT,INDIA sive bromine migration or decomp~sition.~ Some 1,2,3,5-tetrabromo-4,6-dinitrobenzene was found (7) G. T. Morgan and H. D. K. Drew, J . Chem. Soc.; in the reaction products, as well as some unidenti117, 784 (1920). fied low melting by-products which were not separable by the usual means. An investigation of reaction conditions showed that the optimum rate of Nitration of 1,3,5-Trihalobenzenes nitration was obtained a t a ratio of four moles of nitrate to one of dinitrotribromobenzene. The rate hfARION E. HILLAND FRANCIS TAYLOR, JR. of nitration was also sharply affected by the reaction temperature. At temperatures below 120' Received January 4, 1960 long reaction periods were necessary, but a t 130' and above, extensive decomposition began to The nitration of 1,3,5-tribrornobenzeneby mixed occur and the formation of the side reaction prodacid has previously been hindered by decomposiuct, 1,2,3,5-tetrabromo-4,6-dinitrobenzene, was tion and the migration of the bromine atoms to favored. Optimum reaction was obtained a t 125other positions on the ring under the conditions of 127' for a reaction period of eight to nine hours. nitration emp1oyed.l We have reinvestigated The optimum concentration of potassium nitrate the nitration of symmetrical trihalobenzenes and relative to fuming sulfuric acid was not determined have developed a procedure for the nitration of other than to assume complete utilization of the 1,3,5-tribromobenzene which has greatly reduced nitrate to give NOz+ ions. Millen and others5 bromine migration and decomposition of the have given evidence that twelve weight per cent starting material and extended it to 1,3,5-trichloro- nitric acid in 35% fuming sulfuric acid produces benzene and other sterically hindered compounds. (NO2+)(HS207-) as the only solute, a concentraBy nitrating 1,3,5-tribromo-2,4-dinitro- or 1,3,5- tion of nitrating agent nearly equivalent to that trichlorobenzene in a solution of potassium nitrate used in this study. in fuming sulfuric acid good yields of the corAlthough the two step nitration procedure proresponding lxinitro compounds were obtained, duced sym-trinitrotrichlorobenzene in good yield, compared with 20-3070 over-all yields by previous it was found that 1,3,5-trichlorobenzene could be methods.' The method was found to be useful for trinitrated in 73Y0 yield in one step by the fuming nitrating other aromatic compounds such as 2,4,2',- sulfuric acid-potassium nitrate solution. Optimum 4'-tetranitrobibenzyl which previously had been reaction was obtained by using a molar ratio of converted to the hexanitro compound in low yield.2 quantity of hydrazine hydrate was added dropwise with vigorous shaking. It was kept for about an hour, when the 2-nitro-5-iodo-p-tolylhydrazine which precipitated was filtered, washed well with water, dried, and recrystallized from ethanol-ethyl acetate mixture as orange red needles (2.8 g.) m.p. 163'. Anal. Calcd. for C T H ~ O ~ NI,J :43.3. Found: I, 42.8. The acetyl derivative was crystallized from ethanol as lemon yellow needles, m.p. 217". Anal. Calcd. for C s H l o 0 3 ~ sI, I : 37.9. Found: I, 37.7. The benzoyE derivative was crystallized from ethanol as pale yellow needles, m.p. 199". Anal. Calcd. for C14H1103N31: I, 31.9. Found: I, 31.6. Color reactions in acetone solution with aqueous sodium hydroxide were performed as described earlier.' The various characteristic colors produced are recorded below:
(1) (a) C. L. Jackson and J. F. Wing, Am. Chem. J., 10, 283 (1888). (b) C. L. Jackson and J. F. Wing, Am. Chem. J., 12,7, 167 (1890). (2) K. G. Shipp, Private Communication.
(3) H. J. Backer and S. J. Van der Baan, Rec. trav. chim., 56,1175 (1937). (4)C. Weygand, Organic PTeparation, Interscience Publishers, Inc., New York, N. Y . , 1945, p. 279. ( 5 ) D. J. Millen, J . Chem. SOC.,2589 (1950).
